Centrifugal feeders are known which have a disc and rim concentrically rotatable about intersecting, relatively-inclined axes to distribute articles from the disc to the rim, and thence to a discharge station. So far as I am aware, however, known feeders of this type employ a planar inclined disc, which requires sufficient centrifugal force to overcome gravitational action for delivering the articles outwardly onto the rim, and therefore must rotate at a considerable rate of speed. But the centrifugal and gravitational forces act in the same outward direction at the lower edge of the disc, that is, in the article supply reservoir, and the articles are thrown with some violence against the inside of the rim at this point, and subjected to impact shock. Feeders of this nature are suitable for counting coins or feeding other rugged articles, but are objectionable for handling of articles that are delicate or subject to damage by impact or abrasion.
The general object of this invention is to improve the feeding of articles in serial order from a bulk supply; and more specifically, to feed and align articles with reduced abrasion and impact damage. It is another object to increase the range of permissible feed rates of a serial feeding apparatus.
It is a further object to provide a serial feeding apparatus of improved anti-jamming character.
I mount a disc and an encircling rim in relatively inclined positions, so that the disc attains substantially the same height as the rim at one location around its periphery, constituting an article transfer station, but is elsewhere at a lower elevation, forming a reservoir for articles to be fed. The rim and the disc are rotated in a common angular direction, each about its own major axis of revolution; the axis of the disc is inclined at an angle to the vertical, while that of the rim is preferably substantially vertical. These axes intersect at a point near the upper surface of the disc, so that the parts rotate substantially concentrically, although not coaxially. As thus far generally stated, the apparatus conforms to the prior art.
The upper working surface of the disc, and preferably also that of the rim, is a non-planar surface of revolution, such as a segment of a cone, spheroid, paraboloid, or the like. These working surfaces have their apices directed upwardly, i.e. are upwardly-convex, and are symmetrical about their axes of revolution. The inclination of the axis of the conical or curved disc results in a variation in the inclination or slope of its upper working surface from a minimum at the transfer station, to a maximum at a diametrically-opposite point within the parts reservoir defined between the disc and rim. Consequently this surface may be sufficiently steep as it leaves the reservoir to distribute the articles outwardly against the rim chiefly by gravity, requiring little or no assistance by centrifugal force; but at the same time, the disc surface may become level (or slightly tilted inwardly or outwardly) at the transfer station, to allow a modest centrifugal force to roll or slide the articles out onto the rim without substantial opposition by gravity.
In this connection, it should be borne in mind that gravitational and centrifugal forces aid one another to distribute the articles out against the rim in the reservoir, but oppose one another when the disc surface is also inclined upwardly at the discharge station. Planar tilted discs, having a uniform inclination all around their peripheries, must have a relatively high speed of rotation in order to carry the articles up the incline and discharge them to the rim against the resistance of gravity; but the addition of gravity to the resultingly-large centrifugal force in the reservoir bumps the articles violently against one another and against the rim at that point. A non-planar upwardly-convex form permits the disc to be rotated relatively slowly and thereby to reduce impact and abrasion damage to the articles being fed.
My use of a non-planar upwardly-convex rim also allows the speed of its rotation to be relatively low, since the articles are distributed by gravity against a surrounding rail. The articles are thus arranged in serial order on the rim in an aligned single file, and are thence delivered to a circumferentially-spaced discharge station, with reduced shock, abrasion, and impact against one another. Excess or misaligned parts lying on top of the series of aligned parts on the rim may drop or be deflected back into the reservoir during their passage from the transfer station to the discharge station. The parts may if desired be spaced apart along the line of flow, merely by driving the rim at a higher angular velocity than the disc.